Electric switch device



L SCHON ELECTRIC swmm DEVICE Filed Dec. 6, 1920 Nov. 20 1923.

operations,

Patented Nov. 20, 1923.

UNITED STATES nunwre screen, or

ESSEN, GERMANY, ASSIGNOR T0 FRIED. KBUPI AKTIENGESELL- SCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

ELECTRIC SWITCH DEVICE.

Application file). December 6, 1920. Serial No. 428,668.

; new and useful Improvement in Electric Switch Devices, of which the following is a specification.

The present invention relates to switch devices of the kind serving to cut out an 0 electric circuit, in the case the are produced during the break action is dispersed by a magnetic field. If switch apparatus of this kind be fitted out with metal, say, copper contacts, and if, moreover, they are em- 5 p ed to switch off strong currents at a big voltage then, owing to the fusing,

action of the break arc, there will be produced grooves on the contact surfaces of the aforesaid contacts, even after but a few switch said grooves being disposed in parallel to the dlrection in which the arc controlled by the ma netic field moves, the greatest depth of sai rooves lying at the points where the arc eaves the contacts.

5 The'object of this invention is to prevent in the case of switch apparatus of the kind specified, the formation of such grooves which moreover tend to unduly increase the intermediate resistance.

An embodiment of the subject matter of this invention is shown by way of example diagrammatically in the accompanying drawing, in which:

.Fig. 1 is a vertical longitudinal section,

5 and Fig. 2 a top view of the improved switch structure.

Within a square frame A made of a magnetic material there are oppositely disposed 0 two rods B and C of a non-magnetic material, ofwhich the one, i. e., B, is displace able, and the other, C, stationary. The said rods are provided at their mutually facing ends with resilient bushings b and 0 serv ing to accommodate the switch contact pieces and which are connected by the intervention of sockets b and c to themains conducting to the source of current. Each of said contacts comprises two members D,

0 D and E, E respectively, adapted to project by means of their rectangular extremities into the respective bushings b and 0 in which they are secured byscrews F and G. The contact sections D and E are-made of copper, whereas the sections D and E are made of carbon. Two copper members D and E are arranged to bear up against the contact sections D and E said members D and E reposing with their underside on the bushings b and 0 and being likewise also secured in their position by the screws F and G (Fig. 1). Upon the members D and E there are fixed spark horns 01 and e which are also made of copper. To the inner faces of the frame A, running at right angles to the contact faces of the pieces D, D and E, E respectively, there are oppositely arranged two pole cores a and a surrounded with exciting windings a and a, respectively; these latter being fed with continuous current. The pole cores 0, and a are disposed in suchwise that their vertical planes of symmetry and the contact surfaces of the switch, when closed, will lie in one and the same plane. To either side of the horns d and e there are arranged two upright, semi-circular discs (1 and a, the depending stems of which are fixed on the free polesurfaces of the cores a and a so that these discs come to form members of the pole shoes of the blow out magnet A,

When considering the manner of operation of the device, let the assumption hold that the switch be in the closed position disclosed in the drawing, in which position the p)o1nt of break,bridged by the contact pieces D and E, E is traversed by a strong electrical current of high voltage, and that besides the magnet windings a a are excited. There is thus roduced a magnetic field within the frame the lines of force of which close along the path indicated in dashand-dot lines in Fig. 2.. For the purpose of breaking the current flowing across the contact pieces D, D and E, E the rod B is quickly shifted in the direction denoted by the arrow 00 in Fig. 1. During this motion there is formed an are at the one or the other point of the retiring contact faces of the pieces D, D and E, E the extremities of the are produced resting, as a rule on the copper sections D and E of the contact pieces since the current density will at these points be far greater than at the carbon sec tions D, E. This are is at once driven away from the place where it originates by the magnetic field disposed transversely to the direction of the are; the sense in which the magnetic field acts being sochosen that the arc is driven away in the upward direction. The are therefore quickly attains the upper edges of the contact faces of the members D and E. From here it jumps over to mtgnetic field passing between the discs a an 8 a and is now further driven away by this field in its turn, and goes over to the members D and E and then to the horns (i and c And, since, for this section of the magnetic field, the lines of equal flux density form concentric semi-circles relatively to the discs at, a, the are at this point also assumes a semi-circular shape and is at last ruptured as soon as its extremities have reached the free ends of the horns d and e As will be observed from the foregoing explanation of the operation of the improved switch, the are formed intermediate the contact faces of the copper sections D and E, in consequence of the action of the magnetic field, passes over to the carbon sections D and E of the contact members after such a short space of time, that said are will be unable to exert any fusing action on the copper sections D and E, and that consequently any formation of grooves on these sections will be rendered impossible. On the contrary, and as numerous experiments have conclusively proven, the contact faces of the copper members D and E will remain perfectly untouched and smooth even after numerous breaking actions have occurred of extremely high current intensity and voltage. On the other hand, there is no liability of grooves being formed along the contact faces of the carbon members D and E for the reason that carbon does not melt. All the contact sufaces of the contact pieces D, D and. E, E will therefore remain perfectly sound and intact even in the event of numerous breaks being effected at high current intensities and high voltages, so that the switch device will consequently Dermanently retain its original minimal intermediate resistance.

Should, quite exceptionally, an arc happen to arise intermediate the carbon sections D and E then it is driven in the afore-described manner by the magnet field on to the members D E and the spark horns d and c and there blown out. But even in such a contingency there is no possibility of the contact faces of the copper members D and E being injured. A switch constructed on the lines herein before laid down thus embodies all the advantages residing in the high degree of conductivity pertaining to contact pieces made of metal (copper) without possessing the drawb ck of an increasing intermediateresistance.

I claim:

1. A switch device of the class described comprising a frame, contact pieces mounted in said frame, each contact piece comprising a metal section and a carbon section. one of said contact pieces being movable to lireak the circuit and magnetic means for driving the are formed during the breaking of the circuit from the metal sections of said contact pieces to the carbon sections.

2. A switch device of the class described comprising a frame, contact pieces mounted in said frame, each contact icce comprising a metal section and a car on section, one of said contact pieces being movable to break the circuit by simultaneously disconnecting its metal section and its carbon section from the corresponding metal and carbon sections of the other contact piece and magnetic means for driving the are formed during the breaking of the circuit from the metal sections of said contact pieces to the carbon sections.

3. A switch device of the class described comprising a frame, a set of contact pieces mounted in said frame, one of said contact pieces being movable to break an electric circuit, each contact piece comprising a copper section and a carbon sectlon, means in said frame for establishing a magnetic field disposed transversely to the direction of the are formed when said electric circuit is broken, said magnetic field driving said are from said copper sections of the contact pieces to said carbon sections.

4. A switch arrangement of the class described comprising a frame, a pair of contact pieces supported by said frame, one of said contact pieces being movable to break an electric circuit, each contact piece comprising a copper section and a carbon sectlon, the copper and carbon sections of said contact pieces abutting when said switch is in its closed position, spark horns projecting outwardly from each contact piece and adjacent the carbon sections thereof, electromagnetic devices mounted within said frame on both sides of said contact devices in such a manner that their vertical planes of symmetry and the abutting faces of said contact devices are disposed in the same plane, whereby the arc formed upon the breaking of the electric circuit will be driven upwardly by the magnetic field of said magnetic devices and on to said spark horns.

5. A switch device of the class described comprising a frame, a pair of contact pieces mounted in said frame, one of said contact pieces being movable to break an electric circuit, each contact piece comprising a metal section and a carbon section, the metal and carbon sections of said contact pieces abutting when the switch is in closed position, spark horns projecting from said contact pieces and disposed ad acent the carbon sections thereof, magnetic cores disposed in said frame and transversely to the direction of the arc formed when said electric circuit is broken, windings for said cores, semicircular discs projecting vertically from said cores and disposed on either side of said spark horns, whereby said are will be driven by themagnetic field of said magnetic devices upwardly from the metal sections of said contact pieces to the carbon sections thereof and thence to said spark horns by said semi-circular disc.

6. A switch device of the class described comprising a frame, contact pieces mounted in said frame, each contact piece comprisin a metal section and a carbon section, sai

metal and carbon sections of each contact 20 piece being rigidly connected with each other, one of said contact pieces being movable to break the circuit, means for simultaneously disconnecting the metal section-and the carbon section of said movable contact piece from the corresponding metal and carbon sections of the other contact piece, and magnetic of the other contact piece, and magnetic means for driving the are formed during the breaking of the circuit from the metal sections of said contact pieces to the carbon sections.

The foregoing specification signed at Essen, Germany, this 9th day of July, 1920.

' LUDWIG SGHGN.

In presence of- HANS Gor'rsMANN,

J OHANN DECKERB.

v Certificate of Correction. It is hereby certified that in Letters Patent No. 1,475,144, granted November 20,

1923, ment in requiring correction as follows: Page words and comma 'andmagnetic of upon the application of Ludwig Schon, of Essen,

Electric Switch Devices, an error appears 3, lines 27 and the other contact piece,;

Germany, for an improvein the printed specification 28, claim 6, strike out the and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the Signed and sealed this 8th day of [SEAL] case in the Patent Office.

January,

KARL FENNING, Acting Commissioner of Patents. 

